Empirical Musicology Review Vol. 5, No. 3, 2010 Modes on the Move: Interval Cycles and the Emergence of Major-Minor Tonality MATTHEW WOOLHOUSE Centre for Music and Science, Faculty of Music, University of Cambridge, United Kingdom ABSTRACT: The issue of the emergence of major-minor tonality is addressed by recourse to a novel pitch grouping process, referred to as interval cycle proximity (ICP). An interval cycle is the minimum number of (additive) iterations of an interval that are required for octave-related pitches to be re-stated, a property conjectured to be responsible for tonal attraction. It is hypothesised that the actuation of ICP in cognition, possibly in the latter part of the sixteenth century, led to a hierarchy of tonal attraction which favoured certain pitches over others, ostensibly the tonics of the modern major and minor system. An ICP model is described that calculates the level of tonal attraction between adjacent musical elements. The predictions of the model are shown to be consistent with music-theoretic accounts of common practice period tonality, including Piston’s Table of Usual Root Progressions. The development of tonality is illustrated with the historical quotations of commentators from the sixteenth to the eighteenth centuries, and can be characterised as follows. At the beginning of the seventeenth century multiple ‘finals’ were possible, each associated with a different interval configuration (mode). By the end of the seventeenth century, however, only two interval configurations were in regular use: those pertaining to the modern major- minor key system. The implications of this development are discussed with respect interval cycles and their hypothesised effect within music. Submitted 2010 February 25; accepted 2010 April 26. KEYWORDS: interval cycles, tonal attraction, major/minor tonality, modality INTRODUCTION THE emergence, both theoretical and concrete, of major-minor tonality in seventeenth-century Europe has long preoccupied scholars with a liking for intractable problems. As Gregory Barnett (2002) points out, in his article on the subject in The Cambridge History of Music Theory, musical thought in the seventeenth century seems awkwardly to fall between, and to be dominated by, the solidity of Renaissance modal theory on the one hand and the stable functional tonal world of the eighteenth century on the other. From our perspective, at least, the musical treatises (and music) of the seventeenth century can sometimes appear to be a peculiar and idiosyncratic blend of modality and tonality, and nor are we alone in finding this troublesome. Also in Gregory Barnett’s article is an insightful quotation from the seventeenth-century Italian composer Antonio Maria Abbatini (c. 1609-c. 1679), whose frustration over his then current theoretical predicament was wittily spelled out in a poem to Sig. Bastiano Baldini, c. 1667: Wherever is that age, so beautiful, When lectures in [the art of] music Were in use (and this is not a tale)? Thus the science of composing well Was truly lit from every side; [compare] Our own confusion and unhappy state![1] 62 Empirical Musicology Review Vol. 5, No. 3, 2010 In this article I attempt to tackle the thorny issue of major-minor tonality in the seventeenth century by recourse to a grouping model, referred to as interval cycle proximity (Woolhouse, 2007; Woolhouse, 2009; Woolhouse and Cross, 2010). The topic of the emergence of major-minor tonality is as broad as it is controversial. For some the transition to tonality began as far back as the early fifteenth century, whereas for others the year 1700 is an important threshold (Wiering, 2006). Controversy too surrounds that which preceded common practice period tonality. Modality? For sure – but how, for example, did the modes manifest themselves in medieval plainchant? Were they idealised categories, as is the view expressed in Powers and Wiering (2001) (see also Wiering, 2001), or were they in some way a guiding compositional principle. And if the latter was the case, what was the fit between modes and repertoire? Whatever the answers to these questions, my starting point is that the different aspects of the modal ‘system’ – final, tenor, ambitus, initial melodic gesture, closing formulae, and so on – can be considered subsets of a melody-dominated, overarching diatonic system. This view, which is necessarily a simplification, is taken from Carl Dahlhaus (1990), who states in his monograph Studies on the Origin of Harmonic Tonality: The diatonic system is the embodiment of all the modes. And as a result of the modes’ mutual effects on polyphonic contexts, it can emerge as the dominant factor, the factor with the primary role in determining the overall musical impression. The modal characters of the Dorian, Phrygian and Ionian species of fifths and fourths do not become completely effaced by their joint encounters within the narrow ambitus of a polyphonic composition. Nevertheless, the constant intertwining and crossing of different melodic modes results in a network of interrelationships that assists the diatonic, the comprehensive system, in achieving precedence over the individual modes. (p. 234). It would be an understatement to say that empirical/cognitive studies into the historical emergence of tonality are rare; indeed, to date vanishingly little work has been done to trace the important changes in tonal organisation from the sixteenth to eighteenth centuries employing a cognitive approach. This is understandable. Cognitive musicologists are still debating present-day perceptual matters – what chance have we to elucidate those of a bygone musical era, an era that was confusing even for some of its inhabitants, never mind for us who are removed from it by over three-hundred years of musical culture? However, one notable oasis in the research desert that is seventeen-century cognitive musicology is Huron and Veltman’s (2006) analysis of the pitch-class distributions in Gregorian chants.[2] Whilst Huron and Veltman’s work is not strictly speaking a study of seventeenth-century music, they did find statistical evidence that they hypothesise might have implications for the emergence of tonality at this time. In brief, Huron and Veltman derived eight tone-frequency “mode profiles” from 98 Gregorian chants, randomly selected from the Liber Usualis (Benedictines of Solesmes, 1961). In their initial analysis they found that in general the profiles could be used to predict the conventional mode designations of a randomly selected group of chants – Dorian, Hypodorian, Phrygian, and so on. Furthermore, Huron and Veltman noticed that some of the mode profiles were similar, and, as a result, in a second analysis they asked whether using Euclidean distance measures supramodal groupings might exist under which two or more modes could be subsumed. Employing a multidimensional scaling technique, a two dimensional solution was found that accounted for nearly all of the pitch class distribution variance. One dimension, in particular, was found to account for the majority of the variance: that which separated all the modes with C tenors from the others.[3] Huron and Veltman hypothesized that medieval listeners may have had difficulty differentiating modes with shared tenors and similar profiles, “setting the stage for modal merger […] hundreds of years before Glareanus proposed adding the Ionian and Aeolian modes [in the sixteenth century]” (p. 50).[4] The work presented here aims to compliment that of Huron and Veltman by proposing a possible cognitive mechanism that may account for the way in which the melodic diatonic system, as envisaged by Dahlhaus, developed into the bi-tonic world of major-minor tonality. The article is in three sections: Section 1 contains a brief description of a model of tonal attraction based on interval cycles, and outlines how it might be actuated in cognition; Section 2 shows how the model is consistent with various music- theoretic and empirical features of common practice period tonality; Section 3 sketches some of the important changes in tonal organisation in the seventeenth century and discusses how the changes may, theoretically at least, be accounted for by the model. 63 Empirical Musicology Review Vol. 5, No. 3, 2010 INTERVAL CYCLE PROXIMITY MODEL The word “cycle” implies repetition, and with respect to music the repetition is of pitches whose fundamental frequencies have a 1:2n ratio, where n is an integer greater than 0. In the equal-tempered system (and other related tuning systems, such as Just Intonation) two pitches separated by a frequency ratio of 1:2n are said to be octave-related, and are usually perceived as equivalent to one another. Considerable empirical evidence exists to justify this assertion (see, for example, Allen, 1967; Thurlow and Erchul, 1977; Lockhead and Byrd, 1981; Demany and Armand, 1984; Dowling and Harwood, 1986), and Wright et al. (2000) found evidence for octave generalization in rhesus monkeys. An interval cycle is the minimum number of (additive) iterations of an interval that are required for octave-related pitches to be re-stated. For example, if the interval is a major third (four semitones) and the original pitches are C4 and E4, the first additive iteration of an (ascending) major third states pitch classes E4 and G#/A♭4, the second additive iteration of a major third states pitch classes G#/A♭4 and C5, and the third additive iteration of a major third states pitch classes C5 and E5 – the original pitch classes of the cycle. The interval cycle of a major third, therefore, is three. Note that enharmonic intervals are equivalent. That is, the interval cycle of a given interval is calculated with respect to its absolute size in semitones, not with respect to its intervallic description; for example, C to E♭ = three semitones = C to D#. Therefore, unlike interval descriptions such as “major third” or “perfect fourth”, which are determined by harmonic context, interval cycles are context-independent. Interval cycles endow music with an abstract grouping property, which I refer to as interval cycle proximity (henceforth referred to as “ICP”).